The invention concerns a device for tearing-up and stoking straw into a combustion chamber and comprising an essentially vertical magazine shaft for containing a number of straw bales under which shaft an essentially horizontal slide with teeth is movable from one position vertically below the shaft and into a stoking channel and back again.
Devices of this sort are used especially in connection with straw-burning boilers for feeding the combustion chamber of the boiler with torn-up straw from straw-bales through a stoking channel.
From DK patent publication no. 134.331 and DK patent application no. 2003/81 there are disclosed devices where the cutting-off process is performed by means of a cutting edge, which by the advance of the slide cuts a slice off the straw bale and pushes it forward in the stoking channel.
By the known art there is not produced comminuted straw, but rather separate blocks of straw cut off the bales. This does not give an even and continuous feeding and the combustion of the straw is also poor because of the lump-like straw blocks that are highly compressed due to the baling process. Also, a large amount of power is needed to convey the cutting edge.
To reduce these disadvantages a tearing-up device is disclosed in DK patent application no. 4465/86, said device comprising sawtooth-shaped knives which during their reciprocating movement tear off straw which falls into an underlying hopper and an aggregate for stoking the straw into the combustion chamber. The knives are shaped as mutually parallel saw blades working on the end surface of the straw bale with a sawing motion. This does not give a uniform tearing-off effect and therefore the efficiency is not particularly high on account of this saw-like movement. Thus the power consumption is relatively large in proportion to the quantity of shredded straw.